5. Different goals

Over time, if a couple isn't careful, they might begin to drift apart. This could be due to a lack of communication as other things, such as careers, become more important, or it could be a symptom of a relationship that just isn't working.

If both people are chasing separate goals, such as one wanting to put down roots where they are and the other going after a promotion which could involve relocating, clearly their future is in jeopardy. When this situation is left unchecked, someone is eventually going to have to choose between their ambitions and their significant other.